Substrate polishing metrology using interference signals

• US 8,092,274 B2
• Filed: 11/29/2010
• Issued: 01/10/2012
• Est. Priority Date: 03/28/1995
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Birang, Manoocher, Pyatigorsky, Grigory
• Primary Examiner(s): Wilson, Lee D
• Application Number:
  US12/955,690
• Publication Number:
  US 20110070808A1
• Time in Patent Office: 407 Days
• Field of Search: 451 6- 10, 451/28, 451/41, 451285-288, 451/527, 451/533, 451/537
• US Class Current: 451/6
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B24B 37/205 provided with a window for inspecting the surface of the work being lapped
• CPC Class Codes: B24B 47/12 by mechanical gearing or electric power B24B47/16 takes precedence
• CPC Class Codes: B24B 49/04 involving measurement of the workpiece at the place of grinding during grinding operation
• CPC Class Codes: B24B 49/12 involving optical means
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: G01B 11/06 for measuring thickness ; e.g. of sheet material thickness measurement by thermal means G01B21/085
• CPC Class Codes: G01B 11/0683 measurement during deposition or removal of the layer

Abstract

A polishing pad assembly for a chemical mechanical polishing apparatus includes a polishing pad having a polishing surface and a surface opposite the polishing surface for attachment to a platen, and a solid light-transmissive window formed in the polishing pad. The light-transmissive window is more transmissive to light than the polishing pad. The light-transmissive window has a light-diffusing bottom surface.

Claims

1. A polishing pad assembly for a chemical mechanical polishing apparatus, comprising:

a polishing pad having a polishing surface and a surface opposite the polishing surface for attachment to a platen; and

a solid light-transmissive window formed in the polishing pad, the light-transmissive window being more transmissive to light than the polishing pad, the light-transmissive window having a light-diffusing bottom surface.

2. The polishing pad of claim 1, wherein a top surface of the light-transmissive window is flush with the polishing surface.

3. The polishing pad of claim 1, wherein the bottom surface of the light-transmissive window is flush with the surface opposite the polishing surface.

4. The polishing pad of claim 1, wherein the light-diffusing bottom surface comprises an abrasion of the window.

5. The polishing pad of claim 1, wherein the polishing pad comprises a cover layer with the polishing surface and a backing layer adjacent the cover layer, and wherein the window is formed in the cover layer and an aperture is formed in the backing layer and aligned with the window.

6. A chemical mechanical polishing system, comprising:

a platen;

a polishing pad according to claim 1 secured to the platen;

a polishing head which during polishing holds a substrate against the polishing pad on the platen;

an interferometer capable of generating a collimated light beam which during polishing is directed at and impinges on a side of the substrate that is being polished, the interferometer generating an interference signal; and

a data processor programmed to compute a measure of uniformity from the interference signal.